The invention relates to the field of heat exchangers for a motor vehicle.
It relates more particularly to a heat-exchange module of the type comprising a first heat exchanger having a core mounted between two manifold chambers, onto which core is assembled at least one second heat exchanger having a core mounted between two manifold chambers, in such a way that the same airflow can pass over the respective bodies of the said exchangers.
It is known to assemble onto a first heat exchanger, such as a radiator for cooling a motor-vehicle engine, at least one second heat exchanger so as to constitute an assembly, called a module, ready to be installed into the vehicle. This second heat exchanger most often consists of a condenser for an air-conditioning installation, or else of a cooler of air for supercharging the engine.
In the module thus constituted, the second heat exchanger can be arranged either upstream or downstream of the first heat exchanger, as the case may be, with respect to the direction of movement of the airflow.
The assembling of the second heat exchanger onto the first heat exchanger is usually carried out by way of affixed lugs which are generally integral with the second exchanger. These lugs are then fixed onto the manifold chambers of the first exchanger by fixing means, such as screws, rivets, etc. Such an assembly method constitutes an operation which is expensive and hardly compatible with the high rates dictated by the assembly lines of the motor-vehicle industry.
Furthermore, such an assembly method is suited essentially when the manifold chambers of the first heat exchanger are produced by moulding from a plastic material.
However, the current tendency is to use heat-exchange modules in which the first exchanger and the second exchanger are produced by brazing, starting with metal pieces, generally of an aluminium-based material.
The object of the invention is especially to overcome the abovementioned drawbacks.
It aims in particular to obtain a heat-exchange module in which the assembling of the first heat exchanger and of the second heat exchanger is simplified by comparison with the known solutions.
It also aims to obtain such a heat-exchange module in which the first heat exchanger and the second heat exchanger are produced entirely from a metal material, advantageously aluminium-based, and in which the heat exchangers and their assembly are obtained by brazing.
To that end the invention proposes a heat-exchange module of the type defined in the introduction, in which the manifold chambers of the first heat exchanger are each formed from two shaped sheet-metal pieces and each comprise at least one lug originating from one of the sheet-metal pieces and folded into a housing of matching shape which each of the manifold chambers of the second heat exchanger includes.
Thus, in accordance with the invention, lugs are fashioned directly on the manifold chambers of the first heat exchanger which will serve to position and to retain the second heat exchanger during and after the brazing of the module.
These lugs originate from one of the sheet-metal pieces constituting a manifold chamber of the first heat exchanger, and the corresponding housings are formed directly in the manifold chambers of the second heat exchanger.
It is known, in fact, to produce manifold chambers by assembling two shaped and folded sheet-metal pieces, one of which forms the manifold and is joined to the core of the heat exchanger, and the other of which forms a cover intended to co-operate with the first sheet-metal piece so as to delimit a volume.
Advantageously, the manifold chambers of the first heat exchanger each comprise two lugs and the four lugs thus obtained are accommodated respectively in four housings defined by the two manifold chambers of the second heat exchanger.
According to another characteristic of the invention, each lug is provided in an end region of a manifold chamber of the first heat exchanger, and each housing is formed in an end region of a manifold chamber of the second heat exchanger.
The manifold chambers of the first heat exchanger and the manifold chambers of the second heat exchanger preferably extend in perpendicular directions.
It results therefrom that the two fluids which run through the respective bodies of the two heat exchangers circulate in directions which are generally perpendicular to each other.
In one preferred embodiment of the invention, each of the manifold chambers of the first heat exchanger comprises a first sheet-metal piece forming a manifold with a bottom into which opens out the core of the exchanger and two side faces, as well as a second sheet-metal piece forming a cover, the lugs originating from a side face of the first sheet-metal piece.
However, in a variant, it can also be envisaged to provide for at least one of the lugs to originate from the second sheet-metal piece which forms a cover.
Advantageously, each of the lugs comprises two folds in directions which are substantially perpendicular to each other.
Each of the lugs advantageously terminates in a crimping tab, this tab being suitable for being engaged into a housing of the second heat exchanger.
In one preferred embodiment of the invention, each housing is produced in the form of a notch formed in a wall, in particular a tubular wall, of a manifold chamber of the second heat exchanger.
The first heat exchanger and the second heat exchanger are advantageously each formed from metal pieces, in particular of an aluminium-based material, and are joined together by brazing.
The lugs of the first heat exchanger are advantageously brazed into the corresponding housings of the second heat exchanger.
In one preferred application of the invention, the first heat exchanger is a radiator for cooling a motor-vehicle engine, while the second heat exchanger is a condenser of an air-conditioning installation.
According to another aspect, the invention relates to a method of assembling a heat-exchange module as defined above, which comprises the operations consisting in:
a) providing a first heat exchanger having a core mounted between two manifold chambers each formed from two shaped sheet-metal pieces and each comprising at least one lug originating from one of the sheet-metal pieces,
b) providing a second heat exchanger having a core mounted between two manifold chambers, each of which defines at least one housing for accommodating a lug of the first heat exchanger,
c) folding the lugs into the respective housings, and
d) assembling the first heat exchanger and the second heat exchanger by brazing.